1. Field of the Invention
The present invention relates to a hybrid working machine for which engine power and electric power are used in combination.
2. Description of the Related Art
The related art will be described taking an excavator as an example.
As shown in FIG. 7, in the excavator, an upper rotating body 2 is mounted on a crawler type lower traveling body 1 rotatably around a vertical axis which is vertical to the ground. A working attachment 9 including a boom 3, an arm 4, a bucket 5 and including a boom cylinder 6, an arm cylinder 7 and a bucket cylinder 8 for, respectively, actuating the boom, the arm and the bucket is attached to a front part of this upper rotating body 2.
A cabin 10 is mounted on the left side of the front part of the upper rotating body 2, and a counterweight 11 is equipped on a rear end of the upper rotating body.
An engine room 12 is provided on a rear part of the upper rotating body 2, and an engine 13 serving as a power source is installed in this engine room 12 (refer to Japanese Patent No. 3649147 (hereinafter, referred to as Patent Document 1)).
It should be noted that in the present specification, expressions “front and rear” and “left and right” indicate the directions seen from an operator who sits in the cabin 10.
FIG. 8 shows a block configuration of a drive system and a control system in a case of a hybrid type excavator.
A generator motor 14 for performing a generator operation and a motor operation and a hydraulic pump 15 are connected to the engine 13, and driven by the engine 13.
Discharge oil from the hydraulic pump 15 is supplied to hydraulic actuators such as the boom cylinder 6, the arm cylinder 7 and the bucket cylinder 8 shown in FIG. 7 and a left and right traveling hydraulic motor (not shown) through a control valve (which is the collective of plural valves each of which is provided for each of the actuators respectively) 16, so that the hydraulic actuators are driven.
Meanwhile, a power storage device (a power battery) 17 made up of a secondary battery or the like is connected to the generator motor 14 through a controller 18, and a rotation motor 19 serving as a rotation driving source is connected to the generator motor 14 through an inverter 20.
The controller 18 controls charging and discharging operations and the like of the power storage device 17 in accordance with excess and deficiency of generator output of the generator motor 14.
The inverter 20 switches the generator motor 14 between the generator operation and the motor operation, and controls generated power or an electric current as the motor or torque.
Conventionally, hybrid devices mounted in such a hybrid type excavator are installed in the engine room 12 or the like as shown in Japanese Patent Laid-Open No. 2007-107230 (hereinafter, referred to as Patent Document 2).
Here, there is a need for cooling down the power storage device 17 and the controller 18 which generate heat themselves and are sensitive to heat among the hybrid devices, in order to ensure the original performance and the life.
In this case, as a cooling method, an air cooling method for taking in the cooling air from the exterior and passing the air between targeted devices is the most advantageous in terms of cost, space and the like.
In the known techniques shown in Patent Documents 1 and 2, the power storage device 17 and the controller 18 (hereinafter, both may be collectively referred to as the both devices) are arranged side by side on the plane where the other hybrid devices and the hydraulic pump 15 and the control valve 16 serving as hydraulic devices.
However, in the hybrid working machine, since the hybrid devices are added to limited space of the existing machine, installation space for the devices is restricted.
Therefore, in the known techniques with arrangement on the same plane, a lot of devices including the both devices 17, 18 are concentrated on narrow space, and sufficient space for a passage of the cooling air cannot be obtained around the both devices 17, 18.
Thus, flow of the cooling air to the both devices 17, 18 is deteriorated so that cooling efficiency is decreased.
In a case where the devices 17, 18 are each made up of a main body and casing covering the main body, the cooling air indirectly cools down the main bodies over the casings. Thus, the cooling efficiency is also decreased due to this point.
In accordance with these points, the known techniques have a problem that the performance and the life of the both devices 17, 18 are lowered.